feat: #3536245 Expose views empty area as a slot on the custom element

When a Drupal View returns no results, the configured "No results behavior" (empty area) is now exposed as an 'empty' slot on the custom element. Each area handler's render array is converted via createFromRenderArray(), so entity-rendering plugins produce structured custom elements while plain text/HTML falls back to drupal-markup.

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

Closes #3536245

Merge request reports

Loading
Loading